Cartier Tank, Diablo, Santos, Panthère, Cougar, Santos Ronde (Please add your watch in the comments below…)
The Cartier caliber 687 is a thin Swiss made 3-hander quartz movement with a calendar complication (date).
Some of the topics covered in this caliber listing:
Cartier / 687 / Seven (7) Jewels / Swiss
There is also a 2 letter code below the battery. This could be a date code, but it is unconfirmed. Please post the code found on your watch in the comments below.
Not Cartier In-House / Not ETA
Despite lots of confusion online, the caliber 687 is not produced by ETA nor is it a Cartier in-house movement. The 687 is produced by Piaget.
The Piaget version will typically have a P after the number, as in 687P. Ebel also has a caliber 687, which is also sourced from Piaget.
At the time of this post, replacement prices for Cartier branded 687 movements in working condition range from $230 to $329.99 USD.
Keep in mind that you may be able to find Ebel branded versions at a lower price if you just need parts. Also keep in mind that this movement is available with two datewheel options for different date positions. If your watch has a 6:00 date and you can only find a movement with a 3:00 date, you may be able to transfer the original datewheel to the new movement.
It appears that the correct battery for the cal. 687 is a number 315 battery cell. In the example above, the previous person to work on that watch had a 361/362 battery inside. You may also see people using a 341 (SR714SW) cell.
Make sure that the orange battery insulator tab is intact and in place under the battery when changing the cell.